BZOJ2212 [POI2011] Tree Rotations 【treap】

题目分析：

写的无旋treap应该跑不过，但bzoj判断的总时限。把相关实现改成线段树合并就可以了。

代码：

 #include<bits/stdc++.h>
 using namespace std;

 const int maxn = ;

 int n;
 int ch[maxn][],num,val[maxn];

 int son[maxn>>][],sz[maxn],rot[maxn],data[maxn],key[maxn];

 long long ans = ;

 int merge(int r1,int r2){
     if(r1 == ) return r2; if(r2 == ) return r1;
     if(key[r1] < key[r2]){
     son[r1][] = merge(son[r1][],r2);
     sz[r1] = sz[son[r1][]]+sz[son[r1][]]+;
     return r1;
     }else{
     son[r2][] = merge(r1,son[r2][]);
     sz[r2] = sz[son[r2][]]+sz[son[r2][]]+;
     return r2;
     }
 }
 pair<int,int> split(int rt,int k){
     if(k == ) return make_pair(,rt);
     if(k >= sz[rt]) return make_pair(rt,);
     if(sz[son[rt][]] >= k){
     pair<int,int> res = split(son[rt][],k);
     son[rt][] = res.second; res.second = rt;
     sz[rt] = sz[son[rt][]] + sz[son[rt][]] + ;
     return res;
     }else{
     pair<int,int> res = split(son[rt][],k-sz[son[rt][]]-);
     son[rt][] = res.first; res.first = rt;
     sz[rt] = sz[son[rt][]] + sz[son[rt][]] + ;
     return res;
     }
 }
 int found(int now,int x){
     if(now == ) return ;
     if(data[now] == x) return sz[son[now][]];
     if(data[now] < x) return sz[son[now][]]++found(son[now][],x);
     else return found(son[now][],x);
 }

 void dfs(int now){
     int d; scanf("%d",&d);
     if(d){val[now] = d; return;}
     ch[now][] = ++num; dfs(num); ch[now][] = ++num; dfs(num);
 }

 long long alpha,beta;
 void walk(int A,int B){
     int z = found(B,data[A]); alpha += z; beta += (sz[B]-z);
     if(son[A][]) walk(son[A][],B);
     if(son[A][]) walk(son[A][],B);
 }

 void dfs2(int A,int &B){
     if(son[A][]) dfs2(son[A][],B),son[A][] = ;
     if(son[A][]) dfs2(son[A][],B),son[A][] = ;
     sz[A] = ; int z = found(B,data[A]);
     pair<int,int> pr = split(B,z);
     B = merge(merge(pr.first,A),pr.second);
 }

 void dfs1(int now){
     if(val[now]){
     num++;
     key[num]=rand();
     sz[num]=;
     data[num]=val[now];
     rot[now]=num;
     return;
     }
     dfs1(ch[now][]); dfs1(ch[now][]);
     alpha = ,beta = ;
     if(sz[rot[ch[now][]]] < sz[rot[ch[now][]]]){
     walk(rot[ch[now][]],rot[ch[now][]]);
     dfs2(rot[ch[now][]],rot[ch[now][]]);
     rot[now] = rot[ch[now][]];
     }else {
     walk(rot[ch[now][]],rot[ch[now][]]);
     dfs2(rot[ch[now][]],rot[ch[now][]]);
     rot[now] = rot[ch[now][]];
     }
     ans += min(alpha,beta);
 }

 void read(){
     scanf("%d",&n);
     num = ;
     dfs();
 }

 void work(){
     num = ;
     dfs1();
     printf("%lld",ans);
 }

 int main(){
     read();
     work();
     return ;
 }